Single-phase permanent magnet rotor electric water pump only rotating in right direction and its realization method

ABSTRACT

Disclosed are a single-phase permanent magnet rotor electric pump only rotating in a right direction and its realization method. The method comprises the following steps: controlling the size of a water chamber within a water pump body such that a space volume of the water chamber is 3 times or more than that of a space enclosed by each blade of an inner arc water impeller during rotation, and the diameter of the water chamber is 1.2 times or more than that of the water impeller at its common axis; designing the water pump body such that a portion of an inner wall of a water outlet pipe away from the central axis of the water chamber is parallelly deflected outward in a distance Δ from a tangent of the water chamber inner wall, thereby establishing a step structure; selecting a single-phase permanent magnet rotor or a proper torque to drive the arc water impeller within the water pump body, and limiting the fluctuation range of power supply voltage, thus ensuring that electric water pump rotates only in a right rotation direction and against the bending direction of the individual water blade. This method enables the water pump to rotate in the right direction under single-phase AC power supply condition where the fluctuation is up to 20% of the rated voltage.

CROSS-REFERENCE TO RELATED APPLICATION

This Application is a Section 371 National Stage Application ofInternational Application No. PCT/CN2011/076159, filed Jun. 22, 2011 andpublished as WO 2012/174718 on Dec. 27, 2012, not in English, thecontents of which are hereby incorporated by reference in theirentirety.

TECHNICAL FIELD

The present invention relates to a rotary non-variable capacity typepumping device and drag mechanism, in particular, relates to a method ofenabling the forward and opposite rotating drag torque discrepancy ofthe arc-shaped water impeller for the said pumping device to increase,particularly involving the method and apparatus to enable the water pumpdragged by the single-phase permanent magnet rotor motor to only havethe right direction of rotation.

BACKGROUND ART

For the present technology, centrifugal water pumps are dragged bysingle-phase AC permanent magnet synchronous rotor motor, the saidpermanent magnet rotor and water impeller of the said centrifugal waterpump are directly connected coaxially (see FIG. 3). It is simple instructure, light and small, and easy to produce, thus, cost isrelatively lower, and it is widely and extensively used. Nevertheless,starting torque of the said single-phase permanent magnet synchronousrotor motor is almost zero, and any flow turbulence will affect andchange the starting and running direction of the motor rotor, in otherwords, starting and running direction of the motor rotor areindeterminate and random. This is why in the earlier stages of thepresent technology, water impellers of straight-type blades of extremelylow efficiency are adopted by such single-phase permanent magnet rotorelectric water pumps and central part water discharge is adopted,namely, central axis of the drainage holes fall at radial direction ofthe water impeller and presents orthogonal relation with the centralaxis of the water impeller as is shown in FIG. 6. To improve effluentefficiency of water pumps, someone tries to use semiconductor integratedcircuit and/or embedded software to control drag motor of the said waterpump, enabling it to rotate towards the specified direction withoutbeing disturbed, for instance, technologies disclosed by European patentapplication EP 0 574 823 A2 and Chinese patent application200710031484.6, therefore, highly effective arc-shaped water impellerwhose water blades can be bent towards the same direction and tangentialeffluent form can be used as is shown in FIG. 5, thereby, electric waterpumps can be energy-efficient. However, there are problems of obviousincrease of cost, relative complicated structure and declining ofreliability for all of the patented technologies disclosed above.

Under the circumstance of using high efficient water pump structure witharc-shaped water impeller whose water blades can be bent towards thesame direction and tangential effluent form, the first and foremostthing shall be trying to enable the forward and opposite rotating dragtorque discrepancy of the said arc-shaped water impeller to increase,thus, at starting state, when rotor assembly of the said electric waterpump shakes a little, they will naturally rotate towards the directionwhere the drag torque is smaller, and rotate faster and faster tillreaching the synchronous speed. Another issue to be considered shall bethe fluctuation range of the power supply voltage. It is shown byanalysis that if supply voltage of the drag motor deviates from therated value, its drag torque will have greater deviation. Therefore,drag torque of the motor under maximum supply voltage smaller thanopposite drag torque of the water impeller, while drag torque of themotor under minimum supply voltage greater than forward drag torque ofthe water impeller are naturally becoming essential conditions assuringthe reliable operation of the said electric water pumps.

CONTENT OF THE INVENTION

The invention is intended to solve the technical issues by means ofavoiding the deficiencies of the above existing technology, and putforward a method and apparatus of enabling the centrifugal water pumpdragged by the single-phase permanent magnet rotor motor to just havethe right direction of rotation under the condition of no increase ofcost, thus greatly promoting the energy efficiency of such water pumps,and applicable to regions whose supply network voltage fluctuation rangeis greater. The following technical proposal can be adopted for thepurpose of addressing the said technical issues: put forward a method ofenabling single-phase permanent magnet rotor motor to just have theright direction of rotation, including Step:

A. Control the dimension of the water chamber in the water pump, be sureto enable the space volume of the water chamber to be over 3 times ofthe tolerance space of all rotating water blades of the arc-shaped waterimpeller therein, meanwhile, diameter of the said water chamber shall bemore than 1.2 times of the diameter of the water impeller therein, so asto increase the drag torque of the said arc-shaped water impellerrotating towards wrong direction;

B. During the designing of the water pump body, tangential waterdischarge shall be adopted, enabling the part where the inner wall ofthe outlet pipe (set at the radial side of the said water chamber andconnected with the water chamber) is far away from the central axis ofthe said water chamber to deviate parallelly outside from the tangentline of the inner wall of the said water chamber for certain distance A,result in an abrupt structure, further increasing the drag torque of thesaid arc-shaped water impeller rotating towards wrong direction;

C. Choose single-phase permanent magnet rotor motor with appropriatetorque to drag water impeller in the said water pump, limit thefluctuation range of the supply voltage, be sure to enable the dragtorque M_(max) of the said motor under maximum supply voltage to belower than the drag torque N_(opp) for the said water impeller rotatingtowards wrong direction, namely, rotating inversely, while, drag torqueM_(max) under minimum supply voltage greater than forward rotating dragtorque N_(for) of the said water impeller rotating towards rightdirection, the structural shape of the said water chamber and dimensionof the said permanent magnet rotor have assured N_(opp)>>N_(for),therefore:

-   -   M_(max)<N_(opp), M_(min)>N_(for),

Thereby, the said electric water pump rotating in right directionagainst the bending direction of the said water blades is assured; spacevolume of the water chamber stated in Step A refers to all space volumeof the water chamber closed by the water chamber cover.

As to the said abrupt structure in the said Step B, geometricalrelationship thereof satisfies

0.50≧Δ/d≧0.20, where d is the inner diameter of the said outlet pipe;

In the other preferred embodiment, geometrical relationship of theabrupt structure stated in the said Step B satisfies

0.30≧Δ/d≧0.20, where d is also the inner diameter of the said outletpipe.

For another embodiment of the invention, the said method of enabling thesingle-phase permanent magnet rotor electric water pump to only haveright direction of rotation also includes Step:

D. Increase at least one moveable baffle, which can rotate on inner wallof the water chamber along an axial axis; meanwhile, a base plate whosediameter is a little larger than that of the arc-shaped water impelleris set at the back of the said arc-shaped water impeller, when the waterimpeller rotates in opposite direction, water flow thrusts aside themovable baffle, enabling it to cock and withstand the verge of the saidbase plate, hindering the opposite rotation of the water impeller.

The invention has also put forward a high-efficient electric water pumponly having right rotating direction, comprising pump body and a waterchamber which is roughly cylindrical space therein, the water chambercover assembled at the axial outer end of the water chamber has limitedthe space of the water chamber, arc-shaped water impeller on the rotorassembly is accommodated in the space of the said water chambercoaxially, dragged by the permanent magnet rotor of the single-phasesynchronous motor (coaxially installed with the water impeller) torotate; at the radial side of the said water chamber, outlet pipeconnected with the water chamber is set; in particular, space volume ofthe said water chamber is more than 3 times of the tolerance space ofrotating water blades of arc-shaped water impeller therein, meanwhile,diameter D of the said water chamber is more than 1.2 times of thediameter of the coaxial water impeller therein, space volume of thewater chamber described here refers to all space volume of the waterchamber closed by the water chamber cover;

The part where the inner wall of the said outlet pipe is far away fromthe central axis OO′ of the said water chamber deviates parallellyoutside from the tangent line of the inner wall of the said waterchamber for certain distance A, result in an abrupt structure.

For the said abrupt structure, the geometrical relationship whereinsatisfies,

-   -   0.50≧Δ/d≧0.20, where d is the inner diameter of the said outlet        pipe.

In the other preferred embodiment, geometrical relationship of theabrupt structure stated in the said Step B satisfies,

-   -   0.30≧Δ/d≧0.20, where d is the inner diameter of the said outlet        pipe.

In the other preferred embodiment, high-efficient electric water pumpfor the invention with only right rotating direction also comprises atleast one moveable baffle, which is set on the inner wall of the saidwater chamber and rotates around the axial axis on the inner wall of thewater chamber, while a base plate whose diameter is a little greaterthan diameter Dy of the water impeller is set at the back of the saidarc-shaped water impeller, if the water impeller rotates oppositely,water flow will thrust aside the moveable baffle, enabling it to cockand withstand the verge of the water impeller base plate, hindering theopposite rotation of the water impeller.

Compared to the present technology, beneficial effects of the electricwater pump for the invention lie in: high-efficient water pump onlyrotating in right direction under single-phase AC power supply conditionwith the nominal voltage whose fluctuation range is up to 20%.

DESCRIPTION OF FIGURES

FIG. 1 is the orthogonal projection diagram for the overall appearanceof the preferred embodiment of the single-phase permanent magnet rotorelectric water pump of the invention, of which, FIG. 1-1 is the frontview, A-A sectional view of FIG. 1-2; and FIG. 1-2 is the top view;

FIG. 2 is the axonometric projection diagram for the overall appearanceof the said preferred embodiment, of which, FIG. 2-1 is thedecomposition state diagram; and FIG. 2-2 is the post-assemblyaxonometric projection diagram;

FIG. 3 is the axonometric projection diagram for rotor assembly 4 of thesaid electric centrifugal pump, including FIG. 3-1 the decompositionstate diagram; and FIG. 3-2 is the post-assembly axonometric projectiondiagram;

FIG. 4 is the orthogonal projection diagram for the overall appearanceof the other preferred embodiment of the single-phase permanent magnetrotor electric water pump of the invention, in which, FIG. 4-1 is thesectional view (front view) of the arc-shaped water impeller duringforward rotation, at this moment, moveable baffle 33 sinks to the bottomand lies horizontally, FIG. 4-2 is the sectional view (front view) ofthe arc-shaped water impeller during opposite direction rotation, atthis moment the moveable baffle 33 is erected, both of the two Figuresare the A-A sectional view of FIG. 4-3; and FIG. 4-3 is the top view;

FIG. 5 is the orthogonal projection diagram for the overall appearanceof the single-phase permanent magnet rotor electric water pump(arc-shaped water impeller) of the existing technology, of which, FIG.5-1 is the front view, FIG. 5-2 is A-A sectional view; and FIG. 5-2 isthe top view;

FIG. 6 is the orthogonal projection diagram for the overall appearanceof the single-phase permanent magnet rotor electric water pump(straight-shaped water impeller) of the existing technology in the earlystage, of which, FIG. 6-1 is the front view, FIG. 6-2 is A-A sectionalview; and FIG. 6-2 is the top view.

MODE OF CARRYING OUT THE INVENTION MODEL

To further illustrate the principle and structure of the invention, theinvention is further described in detail in accordance with thepreferable embodiments shown in the figures.

For the invention, the method of enabling single-phase permanent magnetrotor electric water pump to only rotate in right direction includesStep A: control the dimension of the water chamber in the water pump, besure to enable the space volume of the water chamber to be over 3 timesof the tolerance space of all rotating water blades of the arc-shapedwater impeller therein, meanwhile, diameter of the said water chambershall be more than 1.2 times of the diameter of the water impellertherein, so as to increase the drag torque of the said arc-shaped waterimpeller rotating towards wrong direction;

B. During the designing of the water pump body, tangential waterdischarge form shall be adopted, enabling the part where the inner wallof the outlet pipe (set at the radial side of the said water chamber andconnected with the water chamber) is far away from the central axis ofthe said water chamber to deviate parallelly outside from the tangentline of the inner wall of the said water chamber for certain distance A,result in an abrupt structure, result in an abrupt structure, furtherincreasing the drag torque of the said arc-shaped water impellerrotating towards wrong direction;

C. Choose single-phase permanent magnet rotor motor with appropriatetorque to drag the water impeller inside of the said water pump body,limit the fluctuation range of the supply voltage, be sure to enable thedrag torque M_(max) of the said motor under maximum supply voltage to belower than the drag torque N_(opp) of the said water impeller rotatingtowards wrong direction, namely rotating oppositely; while drag torqueM_(min) of said motor under minimum supply voltage to be grater than thedrag torque N_(for) of the said water impeller rotating towards rightdirection, namely rotating forward, besides N_(opp)>>N_(for), therefore,

-   -   M_(max)<N_(opp), M_(min)>N_(for),

Thereby, only right direction of rotation against the bending directionof the said water blades within the whole supply voltage fluctuationrange for the said electric water pump is assured.

Space volume of the said water chamber in Step A refers to the all spacevolume of the water chamber after being closed by the water chambercover.

As to the abrupt structure in the said Step B, geometric relationshiptherein satisfies,

0.50≧Δ/d≧0.20, where d refers to the inner diameter of the said outletpipes.

In the other preferred embodiment, geometrical relationship of the saidabrupt structure in the said Step B satisfies

0.30≧Δ/d≧0.20, where d is also the inner diameter of the said outletpipe.

For another embodiment of the invention, the said method of enabling thesingle-phase permanent magnet rotor electric water pump to only haveright direction of rotation also includes Step D. Increase at least onemoveable baffle, which can rotate on the inner wall of the water chamberaround the axial axis; meanwhile, a base plate is set at the back of thesaid arc-shaped water impeller, whose diameter is a slightly greaterthan the diameter of the arc-shaped water impeller, when the waterimpeller rotates oppositely, water flow thrusts aside the moveablebaffle, enabling it to cock and withstand the verge of the said baseplate, hindering the opposite rotation of the water impeller.

For the invention, see FIG. 1 to FIG. 3 for single-phase permanentmagnet rotor electric water pump only rotating in right direction, whichcomprises pump body 2, and water chamber 3 which is roughly cylindricalspace therein, water chamber cover 8 which is assembled at the axiallateral end of the water chamber 3 has limited the space of the waterchamber 3, arc-shaped water impeller 42 on the rotor assembly 4 isaccommodated in the space of the said water chamber 3 coaxially, draggedto rotate by the permanent magnet rotor 41 of the single-phasesynchronous motor (coaxially installed with the water impeller 42;outlet pipe 7 which is connected with the water chamber 3 is set at theradial side of the said water chamber 3; in particular, inner wall 71 ofthe said outlet pipe 7 is far away from the part where central axis OO′of the said water chamber 3 is located, moved outward in parallelly todeviate from the tangent line of the inner wall 31 of the said waterchamber 3 for a distance A, result in an abrupt structure 6, thus,further increasing the resistance of the said arc-shaped water impeller42 rotating towards wrong direction (namely rotating oppositely), so asto assure that the high-efficient water pump rotates merely in the rightdirection against the bending direction of the said water blades 45(namely rotating forward).

Space volume of the said water chamber 3 is more than 3 times of thetolerance space of all water blades 45 for arc-shaped water impeller 42therein during rotation, meanwhile, diameter D of the said water chamberis more than 1.2 times of diameter Dy of the coaxial water impellertherein, space volume of the said water chamber 3 herein refers to allspace volume of the water chamber 3 after being closed by the waterchamber cover 8;

For the said abrupt structure 6, the geometrical relationship thereinsatisfies,

-   -   0.50≧Δ/d≧0.20, where d is the inner diameter of the said outlet        pipe 7.

In the other preferred embodiment, geometrical relationship of the saidabrupt structure satisfies,

-   -   0.30≧Δ/d≧0.20, where d is the inner diameter of the said outlet        pipe.

In another preferred embodiment as is shown in FIG. 4, single-phasepermanent magnet rotor electric water rotating only in right directionalso comprises at least one moveable baffle 33 which is set on the innerwall of the said water chamber and rotates around an axial axis on theinner wall 31 of the water chamber, while a base plate 43 is set at theback of the said arc-shaped water impeller 42, whose diameter is aslightly larger than the diameter Dy water impeller 42, if the waterimpeller 42 rotates oppositely, water flow thrusts aside the saidmoveable baffle 33, enabling it to cock and withstand the verge of thebase plate 43 of the water impeller, hindering the water impeller 42 torotate oppositely.

See FIG. 5 and FIG. 6 for the existing technology for single-phasepermanent magnet rotor electric water pump, thereof, arc-shaped waterimpeller and tangential water discharge are adopted by FIG. 5, whilewater impeller with straight-shaped blades and intermediate water outletare adopted by FIG. 6. In FIG. 5, 2 is pump body, 3 is water chamber, 31is inner wall of the water chamber, 32 is tangential outlet pipe, 45 isarc-shaped water blade. In FIG. 6, 2 is pump body, 3 is water chamber,10 is straight-shaped water impeller, 11 is intermediate outlet pipe.Compared to the existing technology, problems for the existingsingle-phase permanent magnet rotor electric water pump are high incost, complicated in structure, and low in reliability.

What is claimed is:
 1. A method of enabling single-phase permanentmagnet rotor electric water pump to rotate only in right direction,including Step: A. control the dimension of the water chamber in thewater pump, be sure to enable the space volume of the water chamber tobe over 3 times of the tolerance space of all rotating water blades ofthe arc-shaped water impeller therein, meanwhile, diameter of the saidwater chamber shall be more than 1.2 times of the diameter of the waterimpeller therein, so as to increase the drag torque of the saidarc-shaped water impeller rotating towards wrong direction; B. duringthe designing of the said water pump body, tangential water discharge isadopted, enabling the part where the inner wall of the outlet pipe (setat the radial side of the said water chamber and connected with thewater chamber) is far away from the central axis of the said waterchamber to deviate parallelly outside from the tangent line of the innerwall of the said water chamber for certain distance A, result in anabrupt structure, further increasing the drag torque of the saidarc-shaped water impeller rotating towards wrong direction; C. choosesingle-phase permanent magnet rotor motor with appropriate torque todrag arc-shaped water impeller in the said water pump, limit thefluctuation range of the supply voltage, be sure to enable the dragtorque M_(max) of the said motor under maximum supply voltage to belower than the drag torque N_(opp) for the said water impeller rotatingtowards wrong direction, namely, rotating oppositely, while, drag torqueM_(min) under minimum supply voltage greater than forward rotating dragtorque N_(for) of the said arc-shaped water impeller rotating towardsright direction, namely rotating forward, the structural shape of thesaid water chamber and dimension of the said permanent magnet rotor haveassured N_(opp)>>N_(for), therefore: M_(max)<N_(opp), M_(min) >N_(for),thereby, the said electric water pump rotating in right directionagainst the bending direction of the said water blades is assured; spacevolume of the said water chamber in Step A refers to all space volume ofthe water chamber closed by the water chamber cover.
 2. The method ofenabling single-phase permanent magnet rotor electric water pump torotate only in right direction according to claim 1 is characterized inthat: for the abrupt structure stated in Step B, geometricalrelationship thereof satisfies, 0.50≧Δ/d≧0.20, where d is the innerdiameter of the said outlet pipe.
 3. The method of enabling single-phasepermanent magnet rotor electric water pump to rotate only in rightdirection according to claim 1 is characterized in that: for the abruptstructure stated in Step B, geometrical relationship thereof satisfies,0.30≧Δ/d≧0.20, where d is the inner diameter of the said outlet pipe. 4.The method of enabling single-phase permanent magnet rotor electricwater pump to rotate only in right direction according to claim 1 ischaracterized in that: it includes Step, D. increase at least onemoveable baffle, which can rotate on inner wall of the water chamberaround an axial axis; meanwhile, a base plate whose diameter is a littlelarger than that of the arc-shaped water impeller is set at the back ofthe said arc-shaped water impeller, when the water impeller rotatesoppositely, water flow thrusts aside the movable baffle, enabling it tocock and withstand the verge of the said base plate, hindering theopposite rotating of the water impeller.
 5. Single-phase permanentmagnet rotor electric water pump rotating only in right directioncomprises pump body and water chamber which is roughly cylindrical spacetherein, water chamber cover assembled at the axial outside end of thewater chamber has limited the space of the water chamber, arc-shapedwater impeller on the rotor assembly is coaxially accommodated in thespace of the said water chamber, dragged to rotate by the permanentmagnet rotor of the single-phase synchronous motor coaxially installedwith the water impeller; outlet pipe which is connected with the waterchamber is set at the radial side of the said water chamber; it featuresthat: space volume of the said water chamber is more than 3 times of thetolerance space of all water blades for arc-shaped water impellertherein during rotation, meanwhile, diameter D of the said water chamberis more than 1.2 times of the diameter Dy of the coaxial water impellertherein, space volume of the said water chamber herein refers to allspace volume of the water chamber after being closed by the waterchamber cover; the part where the inner wall of the said outlet pipe isfar away from the central axis OO′ of the said water chamber deviatesparallelly outside from the tangent line of the inner wall of the saidwater chamber for certain distance A, result in the abrupt structure. 6.The Single-phase permanent magnet rotor electric water pump rotatingonly in right direction according to claim 5 is characterized in that:for the said abrupt structure, the geometrical relationship thereinsatisfies, 0.50≧Δ/d≧0.20, where d is the inner diameter of the saidoutlet pipe.
 7. The Single-phase permanent magnet rotor electric waterpump rotating only in right direction according to claim 5 ischaracterized in that: for the said abrupt structure, the geometricalrelationship wherein satisfies, 0.30≧Δ/d≧0.20, where d is the innerdiameter of the said outlet pipe.
 8. The Single-phase permanent magnetrotor electric water pump rotating only in right direction according toclaim 5 is characterized in that: it also comprises at least onemoveable baffle which is set on the inner wall of the said water chamberand rotates around an axial axis on the inner wall of the water chamber,while a base plate is set at the back of the said arc-shaped waterimpeller whose diameter is a slightly greater than the diameter Dy ofthe water impeller, if the water impeller rotates oppositely, water flowthrusts aside the said moveable baffle, enabling it to cock andwithstand the verge of the base plate of the water impeller, hinderingthe opposite rotation of the water impeller.